等腰三角形的性质有两个:一是等腰三角形的两个底角相等,简写成“等边对等角”;二是等腰三角形顶角的平分线平分底边并且垂直于底边,即等腰三角形顶角的平分线、底边上的中线和底边上的高互相重合,简写成“三线重合”. There are two isosceles triangles in nature: one is that the two base angles of the isosceles triangle are equal, abbreviated as the “equilateral isometry”; the other is that the bisector of the isosceles triangle vertex bisects the base and is perpendicular to the base. Edge, that is, the bisector of the isosceles triangle’s top corner, the centerline on the bottom edge, and the height on the bottom edge are coincident with each other, abbreviated as “three-line coincidence”.